In the laying and assembly of great lengths of pipe, adjacent sections must be joined in a substantially leak-proof manner, such as by welding. Oftentimes, the solution is the creator of its own set of problems. In this instance, defects often develop in the welds, such as in the girth welds joining adjacent sections. Presently, in order to repair or replace such defects, entire strings of pipe are often removed from their bed, the necessary repairs or replacements performed, and then the repaired or substituted material returned and welded in place. It obviously is desirable to be able to make a welding repair in place. The solution to this problem is the prime purpose of this invention.